Multiplaten press



MULTIPLATEN PRESS 5 Sheets-Sheet 1 Filed NOV. 30, 1962 INVENTORS 0770HAMMO/V W/lL/AM COL 557?? DUANE GAMBREl L ATTORNEY Aug. 24, W65 0.HAMMON ETAL MULTIPLATEN PRESS 5 Sheets-Sheet 2 Filed Nov. 50, 1962 m m Mm 0770 HAM/MON WILL/AM COLBERT DUANE GAME/FELL 1965 o. HAMMON ETAL3,202,03g

MULTIPLATEN PRESS Filed NOV. 30, 1962 5 Sheets-Sheet 5 H ]VEI\7TOR.S-0770 HAMMO/V WILL/AM COLEL'AT BY DUANE GAME/Pill.

ATTOR/VE') 1965 o. HAMMON ETAL 3,202,088

MULTIPLATEN PRESS Filed NOV. 30, 1962 5 Sheets-Sheet 4 07'7'0 HAMMO/VW/LL/AM COLEERT BY awe/v5 GAMER-5Z4 ATTORNEY Aug. 24, 1965 o. HAMMONETAL MULT I PLATEN PRES S 5 Sheets-Sheet 5 Filed NOV. 30, 1962 MOTORINVENTORS O T 7' O HA MMO/V MLL/AM COL BERT BY DUANE GAME/PEA L ATTORNEYUnited States Patent 3,202,088 MULTIPLATEN PRESS Otto Hammon, ScotchPlains, N.J., William H. Colbert, Wilmington, Dell., and Duane Gambrell,Media, Pa assignors to Baldwin Lima Hamilton Corporation, Eddystone,Pa., a corporation of Pennsylvania Filed Nov. '30, 1962, Ser. No.241,217 8 Claims. (Cl. 10053) This invention relates to a multiplatenpress, and more particularly, to a multiplaten press wherein a pluralityof superimposed platens are caused to move toward and.

away from each other uniformly.

Multiplaten hot presses of the general type of the present inventionhave been proposed heretofore. For example, see US. Patents 2,586,474;2,884,032 and 2,913,027. In the prior art, there is insufficient stresscontrol in the rods supporting the platens. In each of the two lastmentioned patents, a control setting must be provided for each of therods, whether it be a separate cylinder or a spring adjustment. Suchsettings and adjustments are time consuming and difiicult to attain ifthe platens are to move uniformly at the same speed toward and away fromeach other.

The presses provided heretofore have overlooked the compressive stresseson the platen supporting rods when the product between two juxtaposedplatens is thicker than the other products. In accordance with thepresent invention, lever arms are hydraulically actuated uniformly sothat the distance between any two platens changes the same amount duringthe stroke of the press thereby preventing products between the lowerplatens from being subjected to extra pressure from the weight of theplatens thereabove during the upward stroke of the crosshead.

A fixed hydraulic preload is provided to allow for the weight of theplatens and the product plus a safety factor. Hence, even if someplat-ens do not contain a product, the stress on these platen supportmembers, such as the chains as provided by the present invention, cannotsubstantially rise above that allowed by the preload in the hydraulicsystem for actuating the lever arms. By using chains as the supportmember for the platens, the large number of individual hydrauliccylinders as disclosed in Patent 2,913,027 and buckling stresses insupport rods are eliminated.

It is an object of the present invention to provide a novel multiplatenhot press.

It is another object of the present invention to provide a multiplatenpress wherein lever arms for actuating movement of the platens areresponsive to and actuated by a. preloaded hydraulic circuit.

It is another object of the present invention to overcome the abovementioned disadvantages of the prior art occasioned by the absence of aproduct between two adjacent platens.

It is another object of the present invention to provide a versatile andsimple hydraulic circuit for causing movement of platens in amultiplaten press.

It is another object of the present invention to provide a multiplatenpress requiring a minimum amount of adjusting time while providing formaximum speed.

It is still another object of the present invention to provide a novelmultiplaten hot press which is capable of being manufactured moreeconomically than those proposed heretofore by overcoming disadvantagesof the prior art.

Other objects will appear hereinafter.

For the purpose of illustrating the invention there is shown in thedrawings forms which are presently preferred; it being understood,however, that this invention is not limited to the precise arrangementsand instrumentalities shown.

FIGURE 1 is a side elevation view of one embodiment of the presentinvention.

FIGURE 2 is an end elevation view of the press illustrated in FIGURE 1.

FIGURE 3 is a side elevation view of another embodiment of the presentinvention.

FIGURE 4 is an end elevation view of the press shown in FIGURE 3.

FIGURE 5 is a schematic illustration of the hydraulic circuitry for thepress illustrated in FIGURES 3 and 4.

FIGURE 6 is a schematic illustration of the hydraulic circuitry for thepress illustrated in FIGURES 1 and 2.

Referring to the drawing in detail, wherein like numerals indicate likeelements, there is shown in FIG- URES 1 and 2 a press designatedgenerally as 10.

The multiplaten hot press 10 includes a stationary headplate 12supported by .a plurality of columns 14. The columns 14- are supportedby a base 18. A movable bedplate 16 is guided by the columns 14 andactuated toward and away from the headplate 12 by a plurality ofcylinders 20.

A plurality of superimposed platens 22 are supported between theheadplate 12 and the bedplate 16. The sheets of material to becompressed will be disposed in the spaces between the platens 22. Eachof the platens 22 is supported from above at four points by chains 3%.The upper end of the chains are secured to lever arms 24-, 26, 28 and afourth arm not shown. One end of each of the lever arms is pivotablysecured to the headplate 12.

Hence, each lever arm will be connected to each platen by one of thechains 30. Each of the lever arms has coupled to its free end apreloaded hydraulic actuator. Hence, arm 24 is provided with a preloadedhydraulic actuator 32. Actuator 32 includes a piston rod 34 having aclevis at its upper end pivotably connected to the free end of lever arm24.

Piston rod 34 extends into cylinder 36 and terminates at its lowermostend in a piston 35. The cylinder 36 is provided with an extension 38pivotably connected to the bedplate 16. Each of the remaining lever armsis provided wtih a similar preloaded hydraulic actuator. For purposes ofillustration, the actuator for lever arm 28 is designated as 40. Theactuator 40 includes a piston rod 42 having a clevis at its upper endpivotably connected to the free end of lever arm. 28. The piston rod 42terminates at its lower end in a piston 43 which is disposed within acylinder 44. The cylinder 4-4 is provided with an extension pivotablyconnected to the bedplate 16.

The hydraulic circuitry which is coupled to the preloaded hydraulicactuator is shown schematically in FIG- URE 6. The circuitry includes apump 45 driven by a motor 48 with a clutch 5t therebetween. The pump 46has an inlet communicating with a source of motive fluid and an outletcommunicating with conduit 54. Conduit 54 is provided with a bypassrelief valve 56 which limits the maximum pressure of motive fluid inconduit 54.

The specific pressure in conduit 54 may be ascertained by opening needlevalve 58 and viewing gauge 69. Conduit 54 communicates with cylinders 36and] 44 belowthe pistons disposed therein by means of conduits 62 and64. The space above the pistons is in communication with atmosphere byway of vents 66 and 68. A solenoid operated three-way pump by-pass valve69 .is provided in conduit 54 to relieve the load on the pump 46 whenthe pressure of the motive fluid in the cylinders 36 and 44 is within aprescribed range as detected by pressure switch 71.

The operation of the apparatus is as follows:

The apparatus 10 will be in the position illustrated in FIGURES l and 2with the platens 22 spaced from each other. The sheets or layers ofmaterial to be pressed are disposed between the platens. Motive fluid isintroduced into the cylinders to raise the bedplate 16 upwardly inFIGURES l and 2. Pump 46 has previously pressurized conduits 54, 62 and64 so that the pressure in cylinders 36 and 44 is Within a prescribedrange as dictated by balancing the moment arm of lever arms 24 and 26 sothat the effect of the pressure on pistons and 43 is slightly greaterthan the moment arm effected by the weight of the platens and theproducts. The cylinders 36 and 44 and their piston rods move upwardlywith the bedplate 16 and act as rigid members.

Let it be assumed that the product between the two lowermost platens isthinner than the others or is absent. As the bedplate 16 moves towardthe stationary headplate 12, the pressure of the bedplate 16 cannot betransmitted directly through the hydraulic actuators and the lever armsto the chains of the loaded platens during this free portion of thestroke of the bedplate 16. Any such transmission of pressure through thehydraulic actuators immediately raises the pressure in cylinders 36 and4-4 below pistons 35 and 43, respectively. When the pressure incylinders 36 and 44 exceeds a predetermined amount, valve 56 opens torelieve this pressure and the cylinders move relative to theirrespective pistons.

Relief valve 56 is set to open at a particular preload on the hydraulicsystem. When the pressure in the hydraulic system reaches the fixedpreload provided to allow for the wei ht of the platens and the productplus a safety factor, valve 56 opens and the pressure is relieved.Hence, it is not possible to overly stress the chains 30 or cause thepiston rods 34- and 42 to buckle.

In the above-mentioned patents, the rotation of the lever arms isdirectly responsive to movement of the bedplate and, therefore, theplatens therein will not accommodate to different thicknesses ofproducts or the absence of a product without providing a complicatedmeans for taking into consideration the buckling stresses on the variousrods or lever arms.

In the apparatus 10 of the present invention, the stress on the chains30 cannot substantially rise above the fixed preload of the hydraulicsystem if a product is not disposed between two adjacent platens 22.Relief valve 56 is preferably adjustable so as to provide a means foravoiding any excessive pre-squeezing of the products which may beundesirable for reasons of uniformity.

After the products have been subjected to pressure and heat whiledisposed between the platens, the above operation is reversed with theweight of the platens and products assisting in the opening movement.When the pressure in cylinders 36 and 44 reaches a predetermined rangeimmediately below the setting of valve 56, the switch 71 actuates valve69 so that the outlet side of pump 46 is in communication with thesource of motive fluid. Hence, there will be no load on the pump 46 solong as the pressure in the cylinders does not fall below thepredetermined range. Accordingly, the cylinders will remain pressurizedat all times. The remaining details relating to the operation of theapparatus 10 are well known to those skilled in the art and need notbedescribed in detail.

In FIGURES 3-5, there is disclosed another embodiment of the presentinvention designated generally as 10 The apparatus 10' is identical withthe apparatus 10 except as will be made clear hereinafter. Accordingly,like elements are provided with corresponding primed numerals.

As shown more clearly in FIGURES 3 and 4, lever arm 24 is provided witha preloaded hydraulic actuator which includes a stationary cylinder 70on one side of the apparatus 10'. A piston rod 72 has one end extendinginto the cylinder 70 and terminates at a piston therein. The other endof piston rod 72 is connected to a transversely extending crossbar 74,as shown more clearly in FIGURE 3. One end of the crossbar 74 ispivotably connected to one end of link '76. The other end of link 76 ispivotably connected to the free end of lever arm 24'. The other end ofcrossbar 74 is similarly interconnected with lever arm 2s by means oflink 78.

Vertical reciprocation of the crossbar 74 is guided by guide rods 80 and82 which are supported at their lower ends by an I-beam 84 on the floorsupport 86. The upper end of the guide rods 80 and 82 is spaced from andinterconnected with the headplate 12'.

A preloaded hydraulic actuator is provided for the lever arm 28 and thelever arm on the same side of the apparatus 10' as arm 28 but not shown.Such actuator includes a cylinder 88 having a piston rod 0 extendingthereinto and terminating at a piston therein. Piston rod 90 isconnected to a crossbar 92 corresponding to crossbar 74. Crossbar 92 isinterconnected with the free end of lever arm 28' by a link 94 whichcorresponds to the link 76.

Vertical reciprocation of the crossbar 92 is guided by guide rods 96which correspond to the rods 80 and 82. The lower end of cylinder 88 issupported by an I-beam 98. Beam 98 is supported by floor support 100.Hence, it will be seen that the apparatus 10' is provided with leverarms which are actuated by a preloaded hydraulic actuator which isseparate and apart from the bedplate 16'.

The hydraulic circuitry for the apparatus 10' is shown schematically inFIGURE 5. The circuitry in FIGURE 5 is substantially identical with thecircuitry in FIG- URE 6 described above. Conduit 54' communicates withthe cylinder 70 below the piston therein by way of conduit 102. Conduit104 communicates cylinder 88 below the piston therein with the cylinders70 and 88 above the pistons therein by means of conduits 106 and 108.

Pump 46' pumps fluid into cylinder 70 by way of conduits 54"and 102.Conduit 102 has a variable restriction 112 therein to control the rateof flow to cylinder 70. As the piston in cylinder 70 rises, it causesthe fluid above the piston to flow into cylinder 88 by way of conduits106, 108and 104 to raise the piston in cylinder 88. Valve 103 is closed.The piston rods 72 and 90 rise at the same speed or slightly faster thanthe speed of bedplate 16'. Motor 48' and the motor for the pumps (notshown) of the cylinders for bedplate 16 may be operated by a singleswitch.

When the press is closed, pressure switch causes valve 103 to openthereby relieving the pressure in cylinders 70 and 88. The fluid incylinder 70 may by-pass restriction 112 by flowing through check valve114'. At the same time, a pressure switch (not shown) or switch 105 willcause motor 48' to stop. The platens and the product will be supportedby the bedplate 16' when. the press is closed.

When the press has closed but suflicient pressure in the cylinders forbedplate 16' has not yet been reached so that switch 105 is actuated,the valve 56' will relieve the pressure load on the pump 48. Valve 56'will also relieve the pressure in cylinder 70 if it becomes greater thanthe predetermined amount as determined by the weight of the products,the weight of the platens and the safety factor as described above withrespect to apparatus 10. The operation and advantages of apparatus 10'is other: wise the sameas that of apparatus 10.

In apparatus 10, the lever arms move in hydraulic synchronization withthe bedplate 16. In apparatus 10' the lever arms move in response tohydraulic actuation which is independent of the bedplate 16'. In eachembodiment of the present invention, a fixed hydraulic preload isobtained by a relief valve arrangement. The bydraulic preload takes intoconsideration the weight of the platens, the product, and a safetyfactor. Hence, even if some of the platens do not contain a product, thestress on the chains 30 or 30 cannot substantially rise above thatallowed by the hydraulic preload in the hydraulic system. As usedhereinafter, the terminology preloaded hydraulic actuator refers to ahydraulic actuator which is pressurized to an initial preload toovercome the weight of the lever arms, chains, platens, and the producton the platens, plus a safety factor.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof and,accordingly, reference should be made to the appended claims, ratherthan to the foregoing specification as indicating the scope oftheinvention.

We claim:

1. In a press comprising a stationary head plate, a plurality of leverarms each having one end pivotably connected to the head plate, aplurality of spaced platens juxtaposed to one another, said platensbeing disposed below said head plate and adapted to be moved upwardlytoward said head plate, a separate flexible member ex tending betweenand directly interconnecting each platen with each arm, at least twopreloaded hydraulic actuators each having one end pivotably coupled to afree end portion of one of said arms for rotating said arms in unison tomove said platens in unision towards and away from said head plate, eachactuator including means to limit the stress to which said members maybe subjected as the platens are moved toward and away from said headplate by rotation of said arms, a bed plate elow the lowermost of saidplatens, and a separate hydraulic means for moving said bed plate towardand away from said head plate.

2. A press in accordance with claim 1 wherein said flexible members arechains.

3. A press in accordance with claim 1 wherein said hydraulic actuatorseach include a hydraulic cylinder, and means pivotably connecting thelower end portion of said cylinder to said bed plate.

4. In a press in accordance with claim 1 wherein said means to limit thestress to which said members may be subjected includes a relief valvefor relieving the pressure of each hydraulic actuator.

5. In a press in accordance with claim 1 wherein said preloadedhydraulic actuators include first and second cylinders on opposite sidesof said platens, each cylinder having a piston rod associated therewith,each piston rod having one end pivotably coupled to said lever arms andeach cylinder having one end portion pivotably coupled to a support.

6. In a press in accordance with claim 1 wherein each actuator includesa cylinder, each cylinder being stationary and having a movable piston,each piston being coupled to one of said lever arms through a cross bar.

7. In a press in accordance with claim 1 wherein each actuator includesa stationary cylinder, a pump coupled to one of said cylinders, a meansseparate from said pump for controlling the rate of flow of fiuid fromsaid pump to said one cylinder.

8. In a press in accordance with claim 7 including conduits coupling theupper end of said one cylinder to the lower end of the other cylinder,and a pressure relief valve coupled to the lower end of each cylinder.

References Cited by the Examiner UNITED STATES PATENTS 2,586,474 2/52Moore 100-200 2,792,777 5/57 Uschmann 10020O 2,884,032 4/59 Thurnher100-499 X 2,913,027 11/59 Thurner 100*-200 X 3,009,495 11/61 Coate100l99 X 3,050,777 8/62 Siempclkamp 18-16 FOREIGN PATENTS 681,547 2/30France. 953,384 11/56 Germany.

WALTER A. SCHEEL, Primary Examiner.

40 A. G. STONE, Examiner.

1. IN A PRESS COMPRISING A STATIONARY HEAD PLATE, A PLURALITY OF LEVERARMS EACH HAVING ONE END PIVOTABLY CONNECTED TO THE HEAD PLATE, APLURALITY OF SPACED PLATENS JUXTAPOSED TO ONE ANOTHER, SAID PLATENSBEING DISPOSED BELOW SAID HEAD PLATE AND ADAPTED TO BE MOVED UPWARDLYTWOARD SAID HEAD PLATE, A SEPARATE FLEXIBLE MEMBER EXTENDING BETWEN ANDDIRECTLY INTERCONNECTING EACH PLATEN WITH EACH ARM, AT LEAST TWOPRELOADED HYDRAULIC ACTUATORS EACH HAVING ONE END PIVOTABLY COUPLED TO AFREE END PORTION OF ONE OF SAID ARMS FOR ROTATING SAID ARMS IN UNISIONTO MOVE SAID PLATENS IN UNISION TOWARDS AND AWAY FROM SAID HEAD PLATE,EACH ACTUATOR INCLUDING MEANS TO LIMIT THE STRESS TO WHICH SAID MEMBERSMAY BE SUBJECTED AS THE PLATENS ARE MOVED TOWARD AND AWAY FROM SAID HEADPLATE BY ROTATION OF SAID ARMS, A BED PLATE BELOW THE LOWERMOST OF SAIDPLATENS, AND SEPARATE HYDRAULIC MEANS FOR MOVING SAID BED PLATE TOWARDAND AWAY FROM SAID HEAD PLATE.